Sealed-end jacked pipe assembly and method of making same

ABSTRACT

An inner tube extending from the end of a protective casing is sealed by first providing two walls between the tube and the casing and filling the space between these walls with a hardenable synthetic resin. Two further walls are provided around the tube outside the casing and a thin body of synthetic-resin material, e.g., a sheet is wrapped around them and again a synthetic-resin mass is introduced into the space between these second walls. Two third walls are provided on the casing and two fourth walls on the tube, with another sheet wrapped around these third and fourth walls. Thereafter synthetic-resin material is again introduced into the space between the third walls and into the space between the fourth walls. Finally synthetic resin is poured into the chamber formed on one side by the second and fourth walls and on the other side by the first and third walls to completely seal the casing end.

United States Patent [191 Butterweck July 23, 1974 SEALED-END J ACKED PIPE ASSEMBLY AND METHOD OF MAKING SAME [76] lnventor: Hellmut Butterweck, Lotharstr. 156,

4100 Duisburg, Germany [22] Filed: June 21, 1972 211 App]. No.: 264,794

[30] Foreign Application Priority Data 'IIIIIIIIII/(i/IIIYIII/(gl! I Martin 138/149.

Primary Examiner-Herbert Goldstein Attorney, Agent, or Firm-Karl F. Ross; Herbert Dubno [5 7] ABSTRACT An inner tube extending from the end of a protective casing is sealed by first providing two walls between the tube and the casing and filling the space between these walls with a hardenable synthetic resin. Two further walls are provided around the tube outside the casing and a thin body of synthetic-resin material, e;g., a sheet is-wrapped around them and again a syntheticresin mass is introduced into the space between these "second walls. Two third walls are provided on the casing and two fourth walls on the tube, with another sheet wrapped around these third and fourth walls. Thereafter synthetic-resin material is again introduced into the space between the third walls and into the space between the fourth walls. Finally synthetic resin is poured into the chamber formed on one side by the second-and fourth wallsand on the other side by the first and third walls to completely seal the casingend.

6 Claims, 10 Drawing Figures PATENIEDJUL 23mm sum 2 or 3 SEALED-END JACKED PIPE ASSEMBLY AND METHOD OF MAKING SAME FIELD or THE INVENTION The present invention relates to a jacketed-pipe installation and, more particularly, to the sealing of an end of such an installation.

BACKGROUND OF THE INVENTION Jacketed pipes are used for carrying hot or cold fluid such as steam or refrigerants. Such arrangements are also employed for conducting electricity by means of supercooling of a conductor tube.

In both such installations it is paramount that the pipe end be tightly sealed. This is necessary in order to preserve the vacuum that is usually maintained between the inner tube and its casing.

OBJECTS OF THE INVENTION It is therefore an object of the present invention to provide an improved end seal for the above-described type of jacketed pipe.

SUMMARY OF THE INVENTION ameters of the spacer'and the two second walls being the same.

A sheet is next wrapped around the second walls and spacing body and a foaming synthetic-resin mass is introduced into the space between the two second walls and allowed to harden. Two longitudinally spaced third walls and two similar fourth walls are fitted around the casing and the sheet, respectively; while a second sheet is preferably wrapped around these third and fourth walls, which have like outer diameters, and a foaming synthetic-resin mass is introduced into the space between the two third walls and into the space between the two fourth walls.

Finally a foaming synthetic-resin mass is introduced into the chamber formed on one side by the first and third walls and on the other side by the second and fourth walls and is hardened.

' Once the foamed masses between the four sets of walls have hardened it is possible to completely clean the exposed surfaces of the inner tube and the outer casing to ensure excellent adherence of the last syn-, thetic-resin mass thereto, without the danger of any of the solvent used for cleaning getting in between the nested pipes.

According to other features of the present invention the two sheets are of a width insufficient to wrap com- 7 DESCRIPTION or THE'DRAWING The above and other object, features, and advantages of the present invention will become apparent from the following description, reference being made to the accompanying drawing in which:

FIG. 1 is a longitudinal section through a pair of nested tubes ready for sealing invention;

FIG. 2 is a top view of the structure of FIG. 1;

FIG. -3 is a section taken along line Ill-III of FIG. 1;

according to the present SPECIFIC DESCRIPTION As seen'in FIGS. 1 3, the jacketed-pipe arrangement according to the present invention has an inner tube 1 of a diameter between '15 and cm and a tube 2 of substantially 8 cm in diameter surrounded by a cas ing 3 of sufficient diameter to be spaced from the tube 1 by at least 2 to 5 and from the tube 2 by a distance of 3 to 6 cm, which tube 2 is itself spaced from the tube 1 by a space of 3 to 6 cm. The inner tube 1 can be used as an electric conductor in a cryogenic powertransmission system, or for the transportof hot or cold fluids. The tube 2 may be a simple conduit for electrical cables or may be a return or vacuum line for the jacketed-pipe system.

FIG. 10 shows how instead of a single tube 1, three tubes 1' of around 20 cm in diameter may be used. Sucha system is especially adapted for three-phase electrical systems in which case the tube 2 would be a vacuum line and supercooled gases would be flowed, as liquids, through the conduits .1'.

FIGS. 4-9 show how the end of the jacketed-pipe is sealed according to the present invention.

First, as seen in FIG. 5, two rings 4 are fitted over the tubes 1 and 2 and slid into the tube 3, into which they fit snugly. A space is left between these fiber rings or glands 4 into which a foaming synthetic resin is injected by means of a needle 21 pierced through the outer ring 4. This forms, as shown in FIG. 6, an annular seal 5 between the rings 4 which constitutes a very tight closure of the end of the tube 3.

Subsequently, as shown in FIG. 6, a spider 7 (7 in FIG. 10) and two further rings 8 are fitted over the tube 1 only. This spider 7 and the rings 8 have an inside diameter which is the same as the outside diameter of the tube 1, and an outside diameter some 5-10 cm greater.

FIG. 7 shows how a plate 6 is wrapped around the spider 7 and rings 8 and formed into a cylindrical sleeve therearound by means of a hose clamp or ring 9. The

length of the plate 6 in the direction of the axes of the tubes 1 and 2 is sufficiently great to extend axially beyond both the rings 8 and the spider 7, and its width is insufficient to wrap completely around these elements so that an axial slot 10 is formed at the upperside of the structure. The end of the sleeve 6 closest to the end of the tube 3 lies outside this tube 3 by a distance of about 10 cm. The tube 2 also lies outside the sleeve 6.

a lateral hole in the casing 3, this hole will be completelycovered. Another pair of rings 14 of like outside diameter but out to fitsnuglyover the tubes 6 and 2 are fitted over the tube 6 with a space left between them that is just in line with the spider 7. The rings 14 could be mounted directly on the tube 1, in which case rings 8 and plate could be dispensed with. A transparent polester plate 12 like the plate 6 is wrapped around the rings 13 and 14, overlapping them'at both ends and forming an axial'slot 18 at the top. Clamps l5 overlying the outermost rings 13 and 4 secure this plate 12 in place. The rings 13 and 14, like rings 8, are applied as polyurethane-foam strips fastened with. contact cemerit. At this time more foaming polyurethane material is poured in between the rings 8, l3, and 14 to define a chamber at the end of the tube 3 which is only open at 11 and 18. This forms a seal 16 between the rings 13, a seal 17 between the rings 14, and a seal. 10 between the seals 8.

The regions of the tubes 1-3 exposed between these seals is now thoroughly cleaned, and as shown in FIG. 9 a collar 19 is fitted to the top of the structure, in line with slot 18. A mass of liquid polyurethane mixed with a foaming agent is poured in through the slot 18 and allowed to harden and cure to form a massive seal 20. Since the slot 10 is open and the spider 7 forms longitudinal passagesallof the air will be driven out and even a nominal amount'of the resin will flow out at this point, howeverdue to the resins viscosity the chamber will fill.

There is formed in this manner an extremely tight seal at the end of the tube 3. Since first a very good seal is formed by the. use of the double rings to ensure that 'a closed chamber existsat the end of the tube 3, the

tubes 1-3 may be cleaned without endangering the installation, and thereafter the massive seal 20 may be poured into place. This seal 20 extends back over the tube 3 inside and outside, and even extends over the tube 1 for a good distance so that the chances of leakage are minute.

a synthetic-resin ring completely filling the region be- 7 tween said first walls; I a pair of longitudinally spaced said tube outside said casing;- a synthetic-resin ring completely filling the spacebetween said second walls; 7

a first sheet wrapped around said second walls;

a pair of longitudinally spaced third walls aroundsaid casing;

a synthetic-resin ring completely filling the space betweensaid third walls;

a pair of longitudinally spaced'fourth walls around said sheet and outside said casing;

a synthetic-resin ring completely filling the space between said fourth walls;

a second sheet wrapped around said third and fourth walls, said first and third walls on one side and said second and fourth walls on the other side defining a chamber; and

a synthetic-resin ber. Y

2. The structure defined in claim 1 wherein said sheets form upwardly open slots.

3. The structure defined in'claim 1, further comprising a spacer body surrounding said tube between said first walls and second walls, said first sheet being wrapped around said second walls and said spacer body. i

4. The structure defined in claim 3 wherein said spacer body is formed with longitudinal passages.

5. The structure defined in claim 1, wherein said second sheet forms an upwardly open slot, said structure further comprising a collar at said slot for introduction of said mass in a liquid state into said chamber.

6. The structure defined in' claim lwherein each of said walls is a ring of foamed polyurethane.

secondwalls around mass completely fillingsaid cham- 

1. A jacketed-pipe structure comprising: a casing having an end; a tube in said casing extending from said end; a pair of longitudinally spaced first walls between said tube and said casing at said end; a synthetic-resin ring completely filling the region between said first walls; a pair of longitudinally spaced second walls around said tube outside said casing; a synthetic-resin ring completely filling the space between said second walls; a first sheet wrapped around said second walls; a pair of longitudinally spaced third walls around said casing; a synthetic-resin ring completely filling the space between said third walls; a pair of longitudinally spaced fourth walls around said sheet and outside said casing; a synthetic-resin ring completely filling the space between said fourth walls; a second sheet wrapped around said third and fourth walls, said first and third walls on one side and said second and fourth walls on the other side defining a chamber; and a synthetic-resin mass completely filling said chamber.
 2. The structure defined in claim 1 wherein said sheets form upwardly open slots.
 3. The structure defined in claim 1, further comprising a spacer body surrounding said tube between said first walls and second walls, said first sheet being wrapped around said second walls and said spacer body.
 4. The structure defined in claim 3 wherein said spacer body is formed with longitudinal passages.
 5. The structure defined in claim 1, wherein said second sheet forms an upwardly open slot, said structure further comprising a collar at said slot for introduction of said mass in a liquid state into said chamber.
 6. The structure defined in claim 1 wherein each of said walls is a ring of foamed polyurethane. 